Walmart tells leafy greens suppliers to use blockchain

Walmart has told all its suppliers of leafy greens to sign up to its blockchain solution by this time next year.

In an open letter, the retailer said it expected all suppliers of fresh leafy greens to Walmart stores and Sam’s Club wholesalers to have end-to-end traceability through blockchain by the end of September 2019.

The initiative, called the Walmart Food Traceability Initiative, hopes to improve product traceability in the event of a food hygiene incident like the E. coli outbreak in romaine lettuce earlier this year. The outbreak led to five deaths and 96 hospitalisations.

In its letter to suppliers, Walmart said all fresh leafy greens suppliers will be expected to be able to trace their products back to the farm of origin “in seconds, not days” by this time next year.

“To do this, suppliers will be required to capture digital, end-to-end traceability event information using the IBM Food Trust network,” it said.

Walmart has been piloting the system in partnership with IBM for the last 18 months, and it has created “a user-friendly, low-cost, blockchain-enabled traceability solution” that will create “shared value” for the sector.

“By quickly tracing leafy greens back to source during an outbreak… impacts to human health can be minimised, health officials can conduct rapid and more thorough root cause analysis to inform future prevention efforts and the implication and associated losses of unaffected products that are inaccurately linked to an outbreak can be avoided,” it said.

Walmart said it is planning a two-stage rollout. Direct suppliers are expected to be able to use blockchain to trace products back one step by the end of January 2019, and to have end-to-end traceability back to farms by the end of September 2019.

Blockchain is a distributed ledger system that allows multiple parties to securely update the same database. Unlike a paper-based ledger, which could take days to trace a single lettuce to the source farm, Walmart said blockchain can provide the same information in as little as 2.2sec.

Frank Yiannas, VP of food safety at Walmart, said in the event of another food recall, Walmart’s blockchain system would allow consumers to know if they had contaminated produce.

In June US authorities told consumers to throw away any lettuce produced in Yuma, Arizona, the source of the outbreak. However, none of the bags of salad had the state of origin on them, said Yiannas. This led to produce being unnecessarily wasted and a loss of consumer confidence in the product regardless of the region in which it was grown.

“In the future, using the technology we’re requiring, a customer could potentially scan a bag of salad and know with certainty where it came from,” he said.